module Opal::Nodes::Helpers

def conditional_send(recvr)
  # temporary variable that stores method receiver
  receiver_temp = scope.new_temp
  push "#{receiver_temp} = ", recvr
  # execute the sexp only if the receiver isn't nil
  push ", (#{receiver_temp} === nil || #{receiver_temp} == null) ? nil : "
  yield receiver_temp
  wrap '(', ')'
end

def current_indent
  compiler.parser_indent
end

def empty_line
  push "\n"
end

def indent(&block)
  compiler.indent(&block)
end

def js_falsy(sexp)
  if sexp.type == :send
    mid = sexp.children[1]
    if mid == :block_given?
      scope.uses_block!
      return "#{scope.block_name} === nil"
    end
  end
  helper :falsy
  [fragment("$falsy("),expr(sexp),fragment(")")]
end

def js_truthy(sexp)
  if optimize = js_truthy_optimize(sexp)
    return optimize
  end
  helper :truthy
  [fragment("$truthy("),expr(sexp),fragment(")")]
end

def js_truthy_optimize(sexp)
  if sexp.type == :send
    mid = sexp.children[1]
    receiver_handler_class = (receiver = sexp.children[0]) && compiler.handlers[receiver.type]
    # Only operator calls on the truthy_optimize? node classes should be optimized.
    # Monkey patch method calls might return 'self'/aka a bridged instance and need
    # the nil check - see discussion at https://github.com/opal/opal/pull/1097
    allow_optimization_on_type = Compiler::COMPARE.include?(mid.to_s) &&
      receiver_handler_class &&
      receiver_handler_class.truthy_optimize?
    if allow_optimization_on_type ||
      mid == :block_given? ||
      mid == :"=="
      expr(sexp)
    end
  end
end

def line(*strs)
  push "\n#{current_indent}"
  push(*strs)
end

def mid_to_jsid(mid)
  if /\=|\+|\-|\*|\/|\!|\?|<|\>|\&|\||\^|\%|\~|\[/ =~ mid.to_s
    "['$#{mid}']"
  else
    '.$' + mid
  end
end

def property(name)
  valid_name?(name) ? ".#{name}" : "[#{name.inspect}]"
end

def valid_name?(name)
  Opal::Rewriters::JsReservedWords.valid_name?(name)
end